Breaking leaf springs

Submitted: Tuesday, Oct 13, 2015 at 23:39
ThreadID: 130587 Views:3727 Replies:7 FollowUps:1
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We have a Traveller Caravan we have had for approx. 5 years and recently to my horror the left front leaf spring, being one of four, had completely split at the centre of the spring where it has a hole in it to secure it to the axle. The Van repair place, said I was lucky not to have had an accident but thankfully one half of the leaf spring had stayed in place. I was discussing my problem with 2 of our friends who have 21.6 and 23.6 Traveller vans and to my surprise the 23' has broken several leaf springs in one episode and the 21' van has broken leaf springs on 2 separate occasions.
I would like to hear from anybody out there that has had similar problems with the Traveller suspension because they are a very expensive van and I would hate to think these leaf spring breakages are far more wide spread than I thought. Our 3 vans like most other vans would be verging on overweight if indeed that is the cause. Any comments please.
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Reply By: mike39 - Wednesday, Oct 14, 2015 at 07:39

Wednesday, Oct 14, 2015 at 07:39
Is that a conventional undersprung (spring pack beneath axle) or an over axle conversion to gain more ground clearance?
mike
AnswerID: 591578

Reply By: Ross M - Wednesday, Oct 14, 2015 at 08:39

Wednesday, Oct 14, 2015 at 08:39
Which ever style of spring mount it is, the problem indicates that the spring pad area is not long enough to hold the spring securely AND provide an inert area tightly clamped to the axle so the centre of the spring around the centre bolt cannot flex/isn't being flexed.
The ONLY reason it will break there, is if there is a deficiency in the clamped area/support.

Although different, same technology, the length, ie front to back of that area on a dual cab ute is at least 120mm long. on trailers and caravans I have seen far less length of the spring support and that WILL allow the centre of the spring leaf to flex and it will surely break.

Poor design if breaking there.
AnswerID: 591580

Reply By: swampy - Wednesday, Oct 14, 2015 at 09:28

Wednesday, Oct 14, 2015 at 09:28
hi
Poor quality manufacture or springs that have been reset more than once have high failure rate .
broken leaves ,broken centre bolts ,broken or loose spring clamps
Springs would not last longer than 3mths
New springs would allways last the longest Australian steel ,Australian made by a recognized maker .Even a poor quality steel works can still stuff it up, if having poor process
The different opinions of manufacturing process does lead to large variations in durability
This experience was from underground 4x4 utes patrol and cruiser .
swampy.
That was 20 yrs ago































AnswerID: 591581

Follow Up By: swampy - Wednesday, Oct 14, 2015 at 09:35

Wednesday, Oct 14, 2015 at 09:35
hi
Always use quality u bolts and double nut them [High tensile nuts with anti sieze ]. And of course u used a hardened washer first .
By comparison many trailer makers use single nyloc nuts with a spring washer that rotates and puts its end into the fishplate hole and therefore renders itself useless .
Use a 3/4 drive ratchet set on u bolt nuts [for good leverage ].

swampy
0
FollowupID: 859602

Reply By: K&FT - Wednesday, Oct 14, 2015 at 09:59

Wednesday, Oct 14, 2015 at 09:59
We have a 21.6 Traveller as well. It is now 5 yo and has the Road runner chassis. We broke a leaf in the right rear spring last year. It was one of the lower leaves and presented no real hazard.

I replaced both springs on that axle with parts from my local supplier of trailer parts. I check the undercarriage before every trip and have seen no further issues. I did retension all the U bolts to be sure all was tight.

The van has done approx 50,000km since new.

frank
AnswerID: 591582

Reply By: TomH - Wednesday, Oct 14, 2015 at 10:03

Wednesday, Oct 14, 2015 at 10:03
is the van within its weight limits???????????
AnswerID: 591583

Reply By: pop2jocem - Wednesday, Oct 14, 2015 at 10:24

Wednesday, Oct 14, 2015 at 10:24
If all these vans are of about the same vintage I wonder if there was a bad batch of springs, either with the material or the tempering process. The other possibility, as has been stated is incorrect original tensioning of the U bolts. Even faulty U bolt material allowing them to loose their tension.

Cheers
Pop
AnswerID: 591587

Reply By: The Bantam - Friday, Oct 16, 2015 at 10:59

Friday, Oct 16, 2015 at 10:59
One thing that must be remembered ...... pretty much all light trailer parts are crap in comparison to that you would find on any passenger car or light commercial.

The springs are of no where near the quality you would fund under the back of your tow vehicle ..... and the suspension designes are crude.

the axle pads and fish plates leave a lot to be desired ...... in geneeral the axle pads are too small and do not have curved edges as you would find on a similar car spring ...... many times the springpads are not even fixed to the axle..... they just sit there by friction and good luck...... the fishplates likewise are just a square of plate with pretty wide tolerances in the holes ...... and the U bolts just dont compare to those from the major vehicle manufacturers ........ and they are in general assembled in envoronments with far poorer qulaity control.

So don't be surprised that you find spring breakages on caravans and trailers .... no matter the price. ... this is an all too common failing

As has been mentioned IF the main sprinf leaf is breaking thru the middle .... this does indicate the spring pack is not properly clamped and supported. ..... there should be no flexing in the centre square of the spring pack.

If you care and if it matters to you, you can improve this by.

making and fitting larger spring pads, of thicker material, grinding a curve on the edges rather than leaving a sharp edge and making sure it is positivly located.

Making up heavier and correctly shaped fish plates that are accurately drilled and have holes not considerably oversized for the u bolts.

Make sure the pads and fishplates are reasonably flat with no lumps bumps or burs.

buying good quality U bolts of the correct size and length ...... fitting them with high tensile plain washers and high tensile nuts and then either use a second nut as a lock nut or a nylock nut as a lock nut ...... AND grease your threads .... any grease will do, never seaze is better.

when you assemble ..... be fussy ..... before you start make sure evrything is flat and smooth ....... make sure everything is aligned straight and central.

and those U bolts need to be evenly tightened and they do need to be pretty tight. ...... hell if you have one use a torque wrench ....... note that most trailer U bolts have coarser threads than the car manufacturers use ..... so you have to cranke em up harder to achieve the same bolt tension.

Because of the crappiness of the materials you need to be a bit fussier to get reliability.

hope this helps.
cheers
AnswerID: 591651

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